This article reviews the development of the British Library's OPAC ser
vices leading up to the launch of OPAC 97, offering access to nine mil
lion bibliographic records, The article attempts to show the value of
a user-centred approach in the project management involved in developi
ng such a service as recommended by Human Computer Interaction (HCI) s
tudies. Evaluation studies of the Online Catalogue, the Network OPAC,
a web prototype interface and of OPAC 97 are reviewed briefly and the
results discussed in relation to the OPAC 97 project. Although the OPA
C 97 interface made use of various HCI recommendations, user feedback
sometimes contradicted these in specific instances, revealing the valu
e of detailed user evaluation in developing services.